The 27-year-old Sale is one of the best pitchers in baseball, with a career ERA of 2.97, a WHIP of 1.06, and a whopping 1,238 strikeouts since debuting in 2010. He will join a Boston rotation that already includes David Price and Rick Porcello, making it arguably the most dangerous in the majors

For Boston, the trade signals a clear desire to keep pushing for the World Series, and with Sale they could be as poised to do so as any team in the American League.

The White Sox, meanwhile, have landed a rising star in Moncada, a 21-year-old Cuban infielder with scary power. Kopech, who is 20, throws as hard as anyone and was a first-round draft pick in 2014.